Encoding (arithmetic coding) that uses calculation symbols is recognized as a data compressing method. Arithmetic coding is a technique wherein an input symbol is coded by dividing the interval between 0 and 1, with 0 inclusive, into small intervals proportional to the occurrence probability of the input symbol. According to arithmetic coding, the process in which the small interval specified by an input symbol that is input just before the considered input symbol is divided into smaller intervals proportional to the occurrence probability of the considered input symbol, is sequentially carried out. As a result, multiple input symbols are coded into one real number.
One of the arithmetic coding methods is known as a “Range Coder.” According to the Range Coder, it is possible to code into an integer by using an interval greater than 1.